The deer mouse (Peromyscus maniculatus) and congeneric species are the most abundant and widely distributed native rodents in North America. As a consequence they impact on many aspects of human health as reservoirs for infectious disease organisms and as laboratory models useful in biomedical research. Deer mice have been maintained in captivity since early in the century and are widely used in physiological, environmental and other studies. The Peromyscus Genetic Stock Center at the University of South Carolina proposes to expand utilization of Peromyscus and improve these animals as a convenient model for health-related research. Six or more Peromyscus stocks will be developed specifically for the study of hantavirus, ehrlichiosis and other diseases for which these animals are hosts, as well as for a variety of other biomedical research projects. Utility of this animal model will be improved through in-house studies of reproduction, including cyropreservation of gametes, and further genetic characterization. The stocks developed will be available to the scientific community for research and educational purposes.